NATURAL
LAW. Phrases like ius naturale, diritto
naturale, droit naturel, Naturrecht, and "natural law" have been used over the centuries to designate
a remarkably persistent doctrine concerning the moral basis of law. However,
it would be wrong to assume either that whenever these phrases are used, they
designate this doctrine or that the doctrine itself has endured without variants
or modifications. Accordingly, a minimal characterization of the doctrine
of natural law would seem called for.

CHARACTERISTICS
OF NATURAL-LAW DOCTRINE

There
is a view, attributed with differing degrees of reliability to certain Sophists
and to Hobbes, that in any society the criterion of justice is provided by
what the laws decree and that to ask of these laws whether they are just or
unjust is an absurdity. "No Law can be Unjust," Hobbes asserted
(Leviathan, Ch. 30). It is obviously a necessary condition of any natural-law
doctrine that this view should be rejected. But does this suffice, or are
there certain further propositions that must be entertained, over and above
the claim that enacted or "positive" law is a suitable object of
moral evaluation, before we have a doctrine that can reasonably be called
one of natural law? Historically, at any rate, it would seem that there are.

Natural
law as a legal code.First, it seems an intrinsic
part of the doctrine (as the word "law" in its title is there to
suggest) that the criterion by reference to which positive laws are to be
judged should itself possess some of the characteristics of a legal code.
In particular, it should exhibit some complexity or be capable of formulation
as a comparatively extended set of rules or precepts, against which existing
codes can then be matched item by item. Thus, a doctrine that the content
of justice could not be expressed in anything more specific than one or two
general adages would scarcely be one of natural law. Again, the criterion
of justice must, like a system of law, be internally coherent; the rules that
constitute it must exhibit consistency. To a natural-law theorist it would
be unacceptable, for instance, that the content of justice should be expressed
in a series of maxims each of which had some a priori obligatoriness but which
might issue in conflicting judgments as to the moral validity of a given law.

The
interpretation of "nature."Second, the
ideal or ethical law, which is contrasted with positive law and provides the
norm in terms of which it is evaluated, is regarded by natural-law theorists
(and this is what the word "natural" is there to indicate) as grounded
in something wider or more general or more enduring than the mere practical
needs of men, whether these be expressed in custom or in convention and agreement.
It is grounded in "nature," and the various interpretations that
have been placed on this word have generated the principal transformations
through which natural-law theory has passed. And here it is pertinent to observe
that the two aspects of the theory--the logical aspect, "What is justice?,"
and the epistemological aspect, "How do we discover what justice demands?"
-- move close together.

Physical
laws and laws of conduct.The simplest and oldest
account of the "naturalness" of justice is to be found in a conception
of the universe which originated with the Stoics Zeno and Chrysippus but is
also to be found in thinkers as late as Montesquieu and Blackstone. The whole
universe, on this view, is governed by laws which exhibit rationality. Inanimate
things and brutes invariably obey these laws, the first out of necessity,
the second out of instinct. Man, however, has the capacity of choice and is
therefore able at will either to obey or to disobey the laws of nature. Nevertheless,
owing to the character of these laws, it is only insofar as he obeys them
that he acts in accord with his reason. "Follow nature" is therefore,
on this view, the principle both of nonhuman behavior and of human morality;
and in this last category justice is included. The laws which apply to man
and which he can and should obey are not identical in content with those which
apply to, for example, planets or bees and which they cannot but obey. Nevertheless,
since the universe is a rational whole, governed by a unitary principle of
reason, the analogies between the laws of nonhuman behavior and those of human
morality are very strong and readily penetrated by the rational faculty with
which man has been endowed.

Critics
of this simple variant of natural-law doctrine (for example, John Stuart Mill,
T. H. Huxley, and Vilfredo Pareto) have usually relied on pointing out an
alleged confusion, which they claim is inherent in it, between two senses
of "law''-- law as the formulation of regularities in nature and law
as the norms or rules to which voluntary behavior ought to conform. To infer
the laws that men ideally ought to obey from the laws that animals visibly
do obey or to think that the former can be based on the latter is (the argument
runs) to fall victim to a simple ambiguity. Although natural-law doctrine
in the form under consideration has undoubtedly gained adherents from a confusion
between prescriptive and descriptive laws, it can avoid that confusion if
certain other propositions are accepted. For instance, it might be held that
the universe is the work of a supreme ruler, whose will we ought always to
obey insofar as we can discern it. His will, however, is not transparent,
but since the universe is his creation, it would be only reasonable (some
would say mandatory) to assume that the phenomena he has placed in it evince
his will in their behavior. Accordingly, if we want guidance about what we
should do, we cannot do better than to look to what they do. Here the distinction
between the two kinds of law is fully respected, and the inference from the
one to the other is warranted only by the metaphysical premise that both kinds
are, and are known to be, expressions of a divine or supernatural will. Thus,
coherence is restored to the doctrine, although only at the price of further
assumptions and greater complexity.

There
is, however, another difficulty in the doctrine as stated, and the various
other formulations the doctrine has received might be regarded as so many
attempts to circumvent this difficulty. The difficulty concerns how we are
to select those aspects of natural behavior or those laws of nature (in the
descriptive sense) which can legitimately serve as guides to moral behavior.
For it is idle to pretend that we can extract a uniform message from nature.
Are we, for instance, to model ourselves upon the peaceful habits of sheep
or upon the internecine conflicts of ants? Is the egalitarianism of the beaver
or the hierarchical life of the bee the proper exemplar for human society?
Should we imitate the widespread polygamy of the animal kingdom, or is there
some higher regularity of which this is no more than a misleading instance?
In the light of these and similar questions, it becomes impossible to regard
the maxim "Follow nature" as a substantive guide to conduct. Moreover,
although these discrepancies in nature considerably reduce the value of natural-law
doctrine from an epistemological point of view, the damage they do to it as
a logical theory would seem fatal, for the nature in terms of which the norms
of justice are defined turns out to be internally inconsistent.

One's
nature and one's end.Accordingly, for natural-law
doctrine to be viable, we need a criterion for distinguishing within nature
(where this is equated with the whole range of natural phenomena) those aspects
to which we can, and those aspects to which we cannot, attach normative significance.
Even in Stoic thought we find some reference to an ideal nature, but the most
sustained effort in the history of Western thought to make a discrimination
of this kind derives ultimately from the teaching of Aristotle. It involves
a further appeal to or invocation of nature, in a more limited and specific
sense -- the sense, that is, in which every kind of thing or species has its
own nature or end and its characteristic excellence is realized in performing
whatever conduces to this end. It was the achievement of St. Thomas
Aquinas that he managed, within a certain framework of thought, to solve what
might be called the "selectivity" problem of natural-law theory
by grafting on to the Stoic principle of "Follow nature" the Aristotelian
concept of nature as a teleological system. The general principles of the
law of nature are, St. Thomas argued, known equally to all through their use
of reason, though with the derivative principles, which are exercises in practical
not speculative reason, the same consensus cannot be expected.

If
the Stoic version of natural-law doctrine is open to criticism on grounds
of its implicit metaphysical assumptions, this would seem to be even truer
of the Thomist version. That phenomena are divided into natural kinds, that
each natural kind is distinguished by the possession of an essence, that the
essence stipulates an end, that virtue and goodness are necessarily linked
with the fulfillment of these ends -- these are some of the assumptions behind
St. Thomas' lex naturae. And none of them are, in an evident way, part
of common-sense belief. Nevertheless, the remarkable persistence of a teleological
mode of thinking can be accounted for only by the fact that it does in many
respects accord with the ways in which we think and speak about the world.
We talk of the natural functions or the proper development of man, of the
needs that it is right to satisfy, or of how certain privations stunt or damage
the personality.

Nature
and reason. It was characteristic of much post-Reformation
thought to abandon a teleological metaphysic, and in the juristic writings
of Hugo Grotius, Samuel von Pufendorf, and Jean-Jacques Burlamaqui natural-law
theory was correspondingly reformulated. The nature or essence of man was
now identified tout court with the possession of reason, and natural
law was held to be whatever is found acceptable by recta ratio or sana
ratio. At this stage the logical and epistemological aspects of
the theory come totally together -- natural law was what reason discovers,
and natural law was discovered by reason. But difficulties remained (as they
did in the general philosophy of the age) over how to interpret "reason,"
which was sometimes equated with intuition, sometimes with the cool observation
of nature, sometimes with the decisions of the law of noncontradiction. In
this respect it is instructive to compare the different arguments employed
by Grotius and Pufendorf in their treatment of, for example, the obligations
that attend speech or the rights of testamentary capacity.

The
state of nature. With the attenuation of the metaphysic that accompanied
natural-law theory, the theory at the same time annexed to itself another
sense of "nature." For natural law became increasingly associated
with the state of nature, which was talked of, possibly even thought of, as
a prehistoric or presocietal phase of human development. Theorists may differ
on whether natural law was observed in the state of nature or merely recognized
and respected in the heart, but we find an association between the two firmly
asserted by Hobbes and Locke.

Law
common to many legal codes. There remains, however,
one further sense in which the norms of justice have been held to be grounded
in nature, distinguished from the preceding by its comparative freedom from
metaphysical overtones: This sense is that in which
nature is identified with the common element in a large variety of codes and
conventions. Such would seem to have been the view of the earlier generation
of Roman jurists whose pronouncements on the nature of law were collected
in the Digest at the order of Emperor Justinian (A.D. 533).

The
Roman legal system contained a remarkable body of law, the ius gentium,
which was employed in those cases in which either one of the litigants was
not a Roman citizen or both were resident aliens of different nationalities.
Although Roman in character, the ius gentium lacked the formality and
technicality of the Roman ius civile and shared some features with
the systems of rules and laws belonging to the peoples whom the Roman Empire
had absorbed. It was apparently the ius gentium that Gaius (c. A.D.
160) took for his model when he contrasted the laws that each people had given
itself (ius civile) with a law of nations -- a law practiced by all
mankind and dictated to all men by natural reason. As one would expect, such
a highly empirical account of natural law did not remain like this for long,
and it drew to itself a philosophical theory. In Ulpian, a century later,
the ius naturale is presented separately from the ius gentium
so as to form, with the ius civile, a tripartite division of law, and
was clothed in the grandiose terminology of Stoicism.

The
status of positive laws. A third characteristic
of natural-law theory is the status that it imputes to particular laws that
fail to comply with the norms of justice. Such laws, although they satisfy
all the acknowledged criteria of legal validity, are held not to be, properly
speaking, laws at all. True, certain natural-law theorists have qualified
this judgment. For instance, the later Scholastics Francisco Suárez
and Cardinal Bellarmine maintained that whereas positive laws that run counter
to prohibitive natural law are null and void, those which fall short of affirmative
natural law are still obligatory although not binding in conscience. However,
by and large it would seem to be intrinsic to the theory to hold that conformity
to natural law is the criterion not merely of a just law but of law itself.
In this respect there is a clear and perennial conflict between natural-law
theory and (in, at any rate, one sense of that phrase) legal positivism where
this is defined in terms of Austin's dictum "The existence of law is
one thing; its merit or demerit another" (The Province of Jurisprudence
Determined, 1832, Lecture V).

However,
on one aspect of this conflict obscurity has been cast by those who write
on "the relation between law and morals" (see, for example, the
works of Roscoe Pound). For it may well be the case that in certain legal
systems, such as that of the United States, such conformity to natural law
is one of the criteria of legal validity acknowledged by the system. It is
no part of legal positivism to deny that in such cases a putative law that
runs counter to natural law is, in point of fact, no law at all; all that
is denied is that its invalidity is directly due to its divergence from natural
law. Or to put the matter the other way around, the claim of natural-law theory
is not that a putative law that is discrepant with natural law but satisfies
all the other legal criteria of validity is invalid, for that is universally
accepted. The claim is that a putative law that is discrepant with natural
law but satisfied all the legal criteria of validity is still invalid.
And this is a more radical claim.

It
has been asserted by some critics, notably Hans Kelsen, that natural-law theory
at this point becomes inconsistent. For a certain set of norms is first introduced
as valid legal rules and then declared to be invalid. Now, certainly this
criticism points to a genuine difficulty that does confront natural law here
-- namely, how the so-called laws whose invalidity it asserts are initially
identified. Obviously, they cannot be identified as laws, nor, it seems, can
they be identified as putative laws, for the criteria in terms of which they
are putatively valid are themselves called in question. However, it seems
possible that natural-law theory can accommodate itself to this criticism
by an adjustment of terms.

On
the other hand, it would be wrong to think of the conflict between natural-law
theory and legal positivism as merely verbal, a dispute between a narrower
definition of law that excludes unjust laws and a broader one that includes
them. There are, as H. L. A. Hart (The Concept of Law, Ch. 9) has effectively
demonstrated, substantive reasons for preferring one definition to the other.
The narrower definition is likely to appeal to a society that has just emerged
from an iniquitous regime and wishes neither to accept the laws of that regime
nor to indulge in retrospective legislation. It avoids the dilemma by declaring
the laws void -- hence, the popularity of natural-law theory in post-Hitler
Germany. But the narrower definition also has its dangers. It suggests that
issues of justice are as readily decidable as those of legality. It totally
denies the painful choices that sometimes have to be made, by magistrates
as well as ordinary citizens, between an evil law and no law at all. And it
has one important consequence which is the opposite of that intended--it makes
any law once accepted as valid free of all further assessment.

CRITICISMS
OF THE THEORY

Besides
the internal difficulties that beset natural-law theory, there are two important
criticisms to which it has been subjected.

Relativity
of laws. It has been argued that natural-law theory
cannot admit that the demands of justice may be relative to time and place
so that what ought to be positive law in one society ought not to be in another.
Kelsen thus contrasted the static character of natural-law theory with the
dynamic character of positivism. Supporters of natural-law theory, however,
often reject the supposition on which this imputation is based. In this century
there has been a specific attempt by Rudolf Stammler to evolve a theory of
"natural law with variable content." Even St. Thomas, in a passage
(Summa Theologica II, 2, 57) which Pius XII commended to the attention
of Catholic jurists in 1955, allowed that the secondary precepts of natural
law might vary with the mutations of human nature, although it is arguable
that the only sense in which he conceded human nature was mutable was that
it could become depraved. However, here, as with most disputes about relativism,
the issue is unclear. Presumably, no absolutist would deny that circumstances
may be relevant to judgments about justice, but, equally, no relativist would
deny that what is just in one set of circumstances would be so if these circumstances
were faithfully reproduced. So the only issue -- and this is not a theoretical
issue -- is precisely what effect a particular change of circumstances would
have on the morality of a specific action. Perhaps, however, it could be held
that a natural-law theorist who admitted very freely that circumstances change
the ethical character of actions had departed considerably from the original
inspiration of the theory. The theory of "natural law with variable content''
certainly seems to transgress the first requirement laid down above for a
natural-law theory.

Law
and morality. Second, it might be argued that natural-law
theory has a tendency to blur the distinction between the two questions "What
ought men to do in society?" and "What actions ought to be enforced
at law?" In other words, it blurs the issue traditionally (though confusingly)
referred to as that of sin and crime. And it has this tendency because, presumably,
it is never quite clear whether natural law is a criterion of just action
or of just law.

Many
natural-law theorists have given at least some recognition to this problem.
For instance, St. Thomas argued that the law can pass judgment only on "external
action," for only God is able "to judge the inner movements of the
will" (Summa Theologica I, 2, 100). And in the writings of Christian
Thomasius, and again in Kant's, the distinction between the inner character
of morals and the external character of law or between imperfect and perfect
duties was made a fundamental principle.

Even
so, it might be argued that natural-law theory is misleading in that it takes
as the starting point for a discussion of what the law ought to enforce a
consideration of what men ought to do, even if it goes on to exempt from the
sphere of legislation certain areas of morality as incongruent with the actual
means of enforcement the law has at its disposal. To many it might seem apparent
that the law has no right, let alone obligation, even of a prima-facie or
attenuated kind, to enforce morality as such.